Antiphospholipid Syndrome (cont.)

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Catherine Burt Driver, MD

Catherine Burt Driver, MD, is board certified in internal medicine and rheumatology by the American Board of Internal Medicine. Dr. Driver is a member of the American College of Rheumatology. She currently is in active practice in the field of rheumatology in Mission Viejo, Calif., where she is a partner in Mission Internal Medical Group.

What causes
and risk factors of antiphospholipid syndrome?

The cause of antiphospholipid syndrome is not completely known. Antiphospholipid antibodies reduce the levels of annexin V, a protein that binds phospholipids and has potent clot-blocking (anticoagulant) activity. The reduction of annexin V levels is thought to be a possible mechanism underlying the increased tendency of blood to clot and the propensity to pregnancy loss characteristic of the antiphospholipid syndrome. Certain genes may be risk factors for the development of antiphospholipid syndrome.

Antiphospholipid antibodies, such as anticardiolipin, have also been associated with decreased levels of prostacyclin, a chemical that prevents the clumping together of normal blood clotting elements called platelets.

What laboratory tests can support the diagnosis of antiphospholipid syndrome?

Patients with the antiphospholipid syndrome can have a variety of antibodies to molecules called phospholipids in their blood. These antibodies include VDRL/RPR (a syphilis test that can be falsely positive in these patients), lupus anticoagulant, prolonged PTT, beta 2 glycoprotein I antibodies, and anticardiolipin antibody. As mentioned above, the anticardiolipin antibody has also been found in patients with the immune disease systemic lupus erythematosus, which is characterized by the production of a variety of abnormal antibodies.

How is antiphospholipid syndrome treated?

The treatment of patients with anticardiolipin syndrome has substantially evolved since cardiolipin antibodies were noted to be clinically important in the mid-1980s. Each manifestation of the antiphospholipid syndrome, and each individual patient with the condition, is treated uniquely.

Because many of the features of illness with anticardiolipin syndrome are associated with an abnormal grouping of normal blood clotting elements (platelets), treatment is often directed toward preventing clotting by thinning the blood. Patients with this disorder have a tendency to form blood clots (thrombosis). The unwanted blood clotting can affect the function of virtually any organ. Medications that thin (anticoagulate) the blood, such as
heparin (Hep-Lock, Liquaemin, Lovenox) and warfarin (Coumadin), are powerful blood thinners that are used for treatment. Aspirin has an effect on platelets that inhibits their grouping (aggregation) and has also been used in low doses to thin the blood of selected patients with less severe disease. Cortisone-related medications, such as prednisone, have been used to suppress the immune activity and inflammation in patients with certain features of the condition. For patients with systemic lupus erythematosus who also have antiphospholipid syndrome, hydroxychloroquine (Plaquenil) has been reported to add some protection against blood clotting.

Other reported treatments include the use of intravenous gamma globulin for selected patients with histories of premature miscarriage and those with low blood-clotting elements (platelets) during pregnancy. Recent research studies, however, suggest that intravenous gamma globulin may be no more effective than a combination of aspirin and heparin.